I think a lot of it will depend on your riding environment. If you're a flat-lander, 18 and 19 will probably never be a problem. I ran a 17 for 5 years until late this summer when I went to an 18. I love it on the highway and for rolling around town, but when I went down to Arkansas last weekend I definitely noticed it was different than in my other trips there. I might keep the 18 on there for the rest of the year and switch back to the 17 for the Arkansas Rally every fall. We'll see. I do like going 80+ in 3rd and over 100 in 4th and then still having another gear to really get gone with the 18.
